/Engine/Plugins/Editor/EditorScriptingUtilities/Source/EditorScriptingUtilities/Public/EditorDialogLibrary.h
Open a modal message box dialog with the given message. If running in "-unattended" mode it will immediately return the value specified by DefaultValue. If not running in "-unattended" mode then it will block execution until the user makes a decision, at which point their decision will be returned.
The result of the users decision, or DefaultValue if running in unattended mode.
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintCallable, DisplayName="Show Message Dialog", Category="Editor Scripting | Message Dialog") static [TEnumAsByte](API\Runtime\Core\Containers\TEnumAsByte)< [EAppReturnType::Type](API\Runtime\Core\GenericPlatform\EAppReturnType__Type) > ShowMessage ( const [FText](API\Runtime\Core\Internationalization\FText) & Title, const [FText](API\Runtime\Core\Internationalization\FText) & Message, [TEnumAsByte](API\Runtime\Core\Containers\TEnumAsByte)< [EAppMsgType::Type](API\Runtime\Core\GenericPlatform\EAppMsgType__Type) > MessageType, [TEnumAsByte](API\Runtime\Core\Containers\TEnumAsByte)< [EAppReturnType::Type](API\Runtime\Core\GenericPlatform\EAppReturnType__Type) > DefaultValue, EAppMsgCategory MessageCategory )